The present invention relates to a brake device in an automotive vehicle including an accelerator pedal and a mechanical transmission.
German patent application No. 44 22 664 discloses a brake device of this type. The prior art brake device is based on the following idea: If identifying the driver's intention to initiate braking is possible already prior to the actual pedal application, the stopping distance may be shortened by an automatically initiated brake application. Therefore, the above-mentioned published application suggests sensing both the speed at which the accelerator pedal is released and the speed at which the right foot of the driver approaches the brake pedal. If both the release speed and the approach speed exceed a determined limit value, the interpretation is that the driver intends to brake. The result is that the brake is automatically actuated by way of a so-called `assistant`, and, namely, the lost travel of the brake system is overcome.
The combination of two signals is necessary because the release speed alone does not furnish a sufficient criterion indicating that braking is indeed intended. On the other hand, it is relatively complicated to design a switch or sensor and arrange it in the pedal area of the vehicle where it senses the speed at which the foot approaches the brake pedal.
Therefore, German utility model No. 89 11 963 U1 discloses the provision of a switch in the driver's radius of action which shall be actuated by the driver intentionally as soon as a situation occurs which leads to assume a source of danger. When the driver actuates the switch in such a situation, an automatic braking operation will the triggered alone due to a criterion which evaluates the speed at which the accelerator pedal is released.
Admittedly, this method is easy to realize. However, the precondition is that the driver's action is purposeful and that he recognizes imminent dangerous situations.
An object of the present invention is to configure the brake device so that the automatic braking operation is triggered only if the driver actually wishes to brake.